Apparatus for continuous emulsification

ABSTRACT

A continuous method for the production of a high-internal-phaseratio emulsion containing approximately 90 to 99 percent internal phase utilizing an apparatus having a series of stacked consecutive-flow mixing chambers of progressively increasing dimensions. The internal phase is added successively to the separate chambers whereas the external phase is added to the first chamber.

United States Patent Bowling [451 Aug. 15, 1972 [54] APPARATUS FOR CONTINUOUS EMULSIFICATION [72] Inventor: George W. Bowling, Circleville,

Ohio

[73] Assignee: The United States of America as represented by the Secretary of the Army [22] Filed: Sept. 8, 1970 [21] App1.No.: 70,297

[52] US. Cl ..259/8, 252/314, 252/359 R, 259/D1G. 30 [51] Int. Cl. ..B0lf 7/16, BOlf 15/02 [58] Field of Search ..259/DlG. 30, 7, 8, 23, 24, 259/43, 44, 66, 67, 107, 108, 4, 9, 10; 261/84; 252/341, 359 R [56] References Cited UNITED STATES PATENTS 2,751,425 6/1956 Rupp ..252/359 R X 3,544,078 12/1970 Stupakis .25 9/4 1,848,100 3/1932 Benner et a1 ..259/D1G. 30

989,126 4/1911 Currie ..259/24 1,097,474 5/1914 Schroder ..259/DIG. 30

Primary Examiner-Robert W. Jenkins Assistant Examiner-Philip R. Coe

Attorney-Harry M. Saragovitz, Edward J. Kelly and Herbert Berl 5 7] ABSTRACT A continuous method for the production of a high-internal-phase-ratio emulsion containing approximately 90 to 99 percent internal phase utilizing an apparatus having a series of stacked consecutive-flow mixing chambers of progressively increasing dimensions. The internal phase is added successively to the separate chambers whereas the external phase is added to the first chamber.

2 Claims, 2 Drawing Figures APPARATUS FOR CONTINUOUS EMULSIFICATION The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to a method and apparatus for the continuous production of an emulsion containing approximately 90 to 99 percent internal phase.

The present emulsification process is accomplished by a stagewise addition of an internal phase to a series of consecutive-flow mixing chambers. The internal phase of the emulsion produced may be any light hydrocarbon oil such as MIL-T6624 JP-4 fuel. The external phase of the emulsion produced may be any aqueous or nonaqueous material suitable for the production of emulsified fuel known as MEF-2, e.g., a mixture of ethylene glycol, water and tallow amine acetate. In combination, these ingredients represent, e.g., 4 percent by weight of the total emulsion. Mixing chambers are arranged in such a manner that the flow of the emulsion will progress through the series of mixing chambers from the smallest to the largest in size. The size of the individual mixing chambers will vary according to the throughput in the individual chamber such that the residence time in the separate mixing chambers is approximately equal. The external phase of the mixture is added to the mixing chamber having the smallest volume and first in the series flow configuration. It is essential that the flow rate to the first mixing chamber into which the internal phase is added, is such that the volume of internal phase is less than 70 percent of the emulsion formed in that mixing chamber so that the formation of an emulsion with the proper internal phase will be insured. The internal phase can then be added to succeeding mixing chambers to raise the concentration of the internal phase after the initial emulsion has been formed.

Each of the individual mixing chambers contain suitable means to agitate the fluid in the mixing chamber at a sufficient shear level to insure adequate emulsification while at a sufficiently low shear level so that the emulsion is not demulsified. Baffles may be positioned in the individual mixing chambers to assure a uniform mixing action and to eliminate the possibility of dead spots. The internal phase of the emulsion may be added to any or all of the mixing chambers and the selection of the form of addition will be dependent upon the individual formulation of the emulsion being produced. In certain cases, it will be necessary that the internal phase be added to alternate mixing chambers to allow a resting or complete reconstitution of the emulsion as the emulsion progresses through the various stages of the emulsification process. The number of mixing chambers can be expanded or contracted as desired. However, it is envisioned that from 7 to 21 mixing chambers will be sufficient to insure adequate emulsification.

It is an object of this invention to provide and disclose a continuous method for the production of a highintemal-phase-ratio emulsion.

It is a further object of this invention to provide and disclose a continuous method for the production of an emulsion containing 90 to 99 volume percent internal phase.

It is a further object of this invention to provide and disclose a system for the continuous production of a high-internal-phase-ratio emulsion.

It is a further object of this invention to provide and disclose a system for the production of an emulsion containing to 99 volume percent internal phase.

Other objects and a fuller understanding of the invention may be had by referring to the following description and claims taken in conjunction with the accompanying drawing in which:

FIG. I shows a prospective view of the emulsification system.

FIG. II shows an enlarged sectional view through 2- 2 of FIG. I.

Referring now to the drawing the system comprises housing 15 having a series of vertically positioned stacked emulsion chambers l to 14 positioned therein. Housing 15 is supported on means 17. Bores 19 connect the series of chambers. For purposes of illustration, the volume of each chamber has been designated on the drawing. Common shaft 16, which extends axially through the interior of chambers l to 14, is operable connected to mixer drive 18. Blade assembly 20 is attached to shaft 16 thereby providing the agitation means. The internal phase is conducted from storage 21, by any conventional power means, e.g., pump 25, into U-shaped feed conduit means 22. Feed conduit means 22 may be positioned on any suitable support, e.g., means 23. Flow meters 1' to 14' are positioned on feed conduit means 22. Said flow meters regulate the flow of the internal phase into the emulsification chambers. Conduit means 1" to 14" connect flow meters 1 to 14' with the emulsification chambers. The external phase is conducted from storage 27 by any conventional power means, pump 29, through conduit 1" into emulsification chamber 1. The flow of the external phase is regulated by flow meter 1". The emulsion exits from chamber 14 by means of outlet 24 and is recovered.

In an illustrative example of the production of an emulsion containing 96 percent internal phase, an external phase consisting of a mixture of about 12.50 percent tallow-amine acetate, 54.75 percent water and 32.75 percent ethylene glycol is fed into chamber 1 until the chamber is completely full. At this point, mixer drive 18 is engaged and common shaft 16 on which impeller blades assembly 20 are affixed within each chamber is rotated at a fixed RPM between 500 and 1000. The specific RPM selected is dependent on the particular emulsion being produced in that the agitation must be less than the critical shear parameter of that emulsion. For a number of formulations this has been shown to be in the range of approximately 10,000 sec. When the chamber is full of external phase material and the shaft rotation begins, JP-4 (internal phase) is fed into chamber 1 at the proper rate for which the unit was designed. For example, the present system is designed for a one gallon-per-minute production rate with a 4 percent by volume emulsion. Therefore, since chamber 1 has a volume capacity of 0.06 gallons, the flow rate of external phase into chamber 1 is 0.04 gallons-per-rninute and the flow rate of the internal phase is 0.02 gallons-per-minute. This procedure has the effect of providing complete agitation of the ingredients within the chamber. When the mixture of chamber 1 has been forced upward into chamber 2, additional JPn4 is added to chamber 2. Chamber 2 has a volume capacity of 0.07 gallons. Chamber 2 receives 0.06 gallons from chamber 1. Therefore, the JP-4 flow rate through conduit 2" is 0.01 gallon -per-minute. This procedure is followed through chamber M where a 96 percent internal phase emulsion is recovered. The exact input of the internal phase into each chamber as you progress upward can be calculated by taking the volume of a specific chamber as shown in the drawing and subtracting it from the volume of the previous chamber, e.g., chamber 5 has a volume of O. l 7 gallons; chamber 6 has a volume of 0.22 gallons; consequently, the internal phase is introduced into chamber 6 at the rate of 0.05 gallons-per-minute to satisfy the 0.22 gallon volume of chamber 6.

Utilization of the present invention has resulted in the obtainment of a cleaner, uniform product than was possible under the batch method. In addition, the present method inhibits the loss of light ends (volatile) of certain ingredients, e.g., JP-4 fuel.

Although I have described my invention with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts and/or formulation of emulsions may be resorted to without departing from the spirit and scope of the invention as hereinafter claimed.

Having described my invention, 1 claim:

ll. An apparatus for the continuous production of emulsions comprising a series of stacked interconnecting chambers of progressively increasing capacity commencing from the bottom to the top of the series, a common shaft extending axially through the stacked chambers, agitating means attached to the shaft and confined within each chamber, means for the introduction of an external phase of an emulsion into the first of the chambers at the bottom of the series, means for the introduction of an internal phase of an emulsion separately into each of the series of chambers, and means for recovery of the emulsion.

2. An apparatus in accordance with claim 1 comprising 7 to 21 chambers. 

2. An apparatus in accordance with claim 1 comprising 7 to 21 chambers. 